The vast majority of melons – and virtually all watermelons - are produced in the field. Some cooler climate crops are grown under tunnels to bring forward harvest and catch early markets. Greenhouse or tunnel cultivation of Cantaloupes is practiced in some countries. A wide variety of flowering types are used, varying from open pollinated and F1 hybrids, to triploid or seedless watermelons which need inter-planting with pollinator varieties.
Melons require long, warm, growing periods and plenty of sunshine. Most crops are grown in temperatures of between 25-35°C.
Plants are frost susceptible and low temperatures can cause growth abnormalities, poor flower and fruit set and, at later stages of growth, hollowing of the pulp. Seed germination is inhibited at temperatures below 15°C. In watermelon, temperatures below 13°C. will stunt growth; significant damage occurs below 7.5°C.
Seed should be planted at around 2.5cm depth and needs warm temperatures of above 11-15 °C to encourage germination. The crop is best planted when temperatures will also encourage rapid emergence and early growth. Increasingly, seed – particularly of more expensive hybrid varieties - is grown on and then planted in plugs prior to transplanting, especially when using plastic mulches.
Spacing is determined by local cultivation practice, the soil’s productive capacity, and factors such as equipment width, irrigation capability and whether mulch is being used.
Spacing will also influence the eventual size and sweetness of the fruit. Close planting will reduce the sugar content of the fruit.
Under trickle irrigation, efficiency of water use is increased, so planting density can also be increased. Plastic mulch can bring forward harvest by around two weeks ensuring growers can catch any early, premium markets. Black and wavelength-selective mulches warm the soil and prevent weed growth.